I hope this will never happen of course, but for who have invested capitals, it may be a question someone have answered accurately to avoid an important loss.
Bitcoin price drop shouldn't be something to worry about because it will surely rebounce. It is when you sell during a price drop and you bought higher than that price that you will be in loss, but if you don't sell a dime, you are not in loss. The odd of bitcoin price going up overtime is higher than the price going down. This means that it's easy for bitcoin to reach $1m, than going to zero.
Totally agree, I think there's no need of worrying about the price of Bitcoin. Because as an investor once you start monitoring the price of Bitcoin it will going to trigger you to sell your Bitcoin when you are not supposed to sell it, while because you have already have this feeling that when the price drop that it will not go high again. which is very wrong, Just buy and hold and remove the mindset of monitoring the market price.